Kenya's worst drought in a decade is having a devastating effect on national parks as humans and animals compete for increasingly scarce natural resources.

Wildlife is straying out of the parks, and cattle and herdsmen are straying in as each tries to search wherever they can for food and water.

In Tsavo East, half the national park's elephants have broken the boundaries.

Three people have been killed in as many months by the animals desperately foraging for food.

Tsavo East is one of Kenya's largest national parks, receiving more than 150,000 visitors each year.

The parched earth and rising dust signal growing conflict between animal and man. What little food remains is being fiercely fought over.

Three years of failed rains has stripped the park of vegetation; where there should be wildlife, there is cattle.

Grazing cattle in national parks may be illegal in Kenya but herdsmen who bring their cows in from outside are desperate and prepared to risk arrest.

"Problems, problems. At home the pastures are bad - there is no water," complained a herdsman illegally grazing his cattle.

Elephant invasion

Elephants are now fleeing the park - the invasion of livestock combined with harsh drought driving them away.

Those that remain try to grab what shade and water they can. Normally there should be 10,000 elephants in the park but many are now heading into human settlements in search of food and water.

Beyond the park's boundaries rangers scour the bush for elephants. The rangers fear up to 50% of the elephants have strayed, and it is having devastating consequences.

Julius Chiptea, senior warden, says three years of failed rains has fuelled a conflict between animals and man.

"The conflict here is that because of this dry spell, wildlife and human are all heading towards the same direction in search of fodder and water.

"So you find that animals go to look for water, human beings are also going to look for water from the same source."

Local people are terrified of the elephants. Some have built look-out posts in trees.

Stella Kisombe's husband was killed by an elephant close to their home

Stella Kisombe was recently widowed after her husband was killed by an elephant a short distance from their home.

She said she was hysterical when she discovered what had happened - first she found his hat and then her husband's mutilated body.

Whenever she sees an elephant now, Stella says she runs and hides.

Only a fifth of the park is protected by fencing, and tragic accidents are hardly surprising. There is pressure to improve security but it is expensive.

These are harsh times for animals and man alike. The elephant population and that of its human neighbour is growing at a staggering rate - feeding tensions over scarce resources in a land ravaged by drought.